Hydraulic control device and control unit, brake-by-wire system and method using the same

Abstract

The application discloses a hydraulic control device, a control unit applying the same and a brake-by-wire system, comprising a hydraulic control reversing valve and a high-pressure accumulator, the hydraulic control reversing valve comprising a valve body, a limiting seat and two valve cores, the valve body having a plurality of communicating cavities, the limiting seat and the two valve cores being sequentially arranged in the first cavity of the valve body along an axis, the two valve cores reciprocatingly sliding along the axis and each having an oil passage extending along the axis direction but not completely communicating, being a first valve core and a second valve core, the first valve core serving as a switch for communication between the internal oil passage and the corresponding oil cavity, the second valve core forming an external oil passage extending along the axis direction with the valve body, the second valve core and the limiting seat serving as switches for communication between the internal oil passage and the external oil passage of the second valve core and the corresponding oil cavity, and the internal oil passage of the high-pressure accumulator being communicated with the first cavity through the second liquid inlet cavity of the valve body. The application solves the problem that the braking efficiency of a heavy-load vehicle is insufficient under the motor power-off working condition in the prior art and cannot meet the forced requirement of emergency braking deceleration.

Description

Technical Field

[0001] This invention belongs to the technical field of hydraulic brake-by-wire systems, specifically relating to a hydraulic control device and the control unit, brake-by-wire system, and method using it. Background Technology

[0002] The rapid development of electrification and autonomous driving technologies in new energy vehicles has placed higher demands on the intelligence, comfort, and safety of vehicle driving. Traditional heavy-duty commercial vehicles (medium-duty trucks, heavy-duty trucks, buses, etc., with a full load capacity of over 6 tons) mostly use pneumatic braking systems. Pneumatic braking systems consist of multiple components such as an air compressor, air tank, and brake control valve, making them complex and expensive. Frequent air release during braking generates noise that affects driving comfort. Furthermore, traditional pneumatic braking systems are difficult to implement brake-by-wire, failing to meet the growing demand for intelligent systems. In contrast, hydraulic braking systems offer advantages such as smooth transmission, high load-bearing capacity, small size, and fast response, making them more suitable for automated control. However, due to the structural limitations of traditional hydraulic braking systems with a single braking power source, key parameters such as pedal force, pedal travel, output displacement, and output braking force are difficult to coordinate, limiting their application in large vehicles weighing over 6 tons.

[0003] To address the issue of a single braking power source, patent CN 119218180 A discloses a hydraulic brake-by-wire system. This system employs a design with dual pressure sources and a brake-by-wire unit, independently controlling their respective braking circuits and providing brake fluid to achieve independent adjustment of the braking pressure of the front and rear wheels. It supports multiple communication methods to ensure stable transmission of control signals. The entire system not only improves braking efficiency but also meets the braking performance requirements of heavy-duty vehicles. However, this hydraulic brake-by-wire system has certain drawbacks: it only addresses the braking difficulties of heavy-duty vehicles under electrified conditions. Once the vehicle loses power, the motor, acting as the power source, will not function, and the system will require a mechanical backup braking method involving manual braking by pressing the brake pedal. For heavy-duty vehicles, the braking efficiency of manually operated braking force is significantly insufficient, and it may even fail to meet the mandatory requirements of GB 12676 for emergency braking deceleration. Summary of the Invention

[0004] To address the shortcomings of the prior art, the present invention provides a hydraulic control device and a control unit, a brake-by-wire system, and a method for using the same.

[0005] The objective of this invention is achieved through the following technical solution: In a first aspect, a hydraulic control device is provided, comprising: A hydraulic directional control valve for regulating the braking path includes a valve body, a limiting seat, and two valve cores. The valve body has multiple interconnected cavities. The limiting seat and the two valve cores are sequentially disposed within a first cavity of the valve body. Both valve cores can reciprocate along the axis of the first cavity and each has an oil passage extending along the axis but not fully connected. These are a first valve core and a second valve core. The first valve core serves as a switch connecting its internal oil passage to the corresponding oil chamber. An external oil passage extending along the axial direction is formed between the outer side of the second valve core and the inner wall of the valve body. The second valve core and the limiting seat together serve as a switch connecting the internal and external oil passages of the second valve core to the corresponding oil chamber. A high-pressure accumulator provides power by regulating the internal hydraulic pressure of the hydraulically controlled directional valve. The internal oil circuit of the high-pressure accumulator is connected to the first cavity through the second inlet chamber of the valve body. The first inlet chamber, the first outlet chamber, the second inlet chamber, and the second outlet chamber of the valve body are all connected to the first cavity; the second inlet chamber and the second outlet chamber form a primary oil circuit and a secondary oil circuit respectively through the internal oil circuit and the external oil circuit of the second valve core; the first outlet chamber and the internal oil circuit of the first valve core together form a low-pressure circuit.

[0006] In some embodiments, the oil in the first inlet chamber pushes the first valve core to move along the axial direction until it contacts the second valve core. At this time, the low-pressure circuit, the primary oil circuit, and the secondary oil circuit are disconnected. Subsequently, the first valve core continues to push the second valve core to move along the axial direction until it contacts the limiting seat. At this time, the low-pressure circuit and the secondary oil circuit are both disconnected, while the primary oil circuit is connected, allowing a small amount of oil in the high-pressure accumulator to enter the primary oil circuit. When the pressure in the second outlet chamber tends to be balanced with that in the high-pressure accumulator, the first valve core pushes the second valve core to disengage from the inner wall of the valve body. At this time, the low-pressure circuit and the primary oil circuit are both disconnected, while the secondary oil circuit is open, allowing the oil in the high-pressure accumulator to enter the second outlet chamber through the secondary oil circuit.

[0007] In some embodiments, when the oil in the first inlet chamber stops pushing the first valve core, the first valve core and the second valve core move in opposite directions along the axis. At this time, the primary oil circuit, the secondary oil circuit and the low-pressure circuit are all in a disconnected state. When the oil pressure in the first inlet chamber drops, the first valve core and the valve core move to their original positions in opposite directions along the axial direction. At this time, the primary oil circuit and the secondary oil circuit are both disconnected, and the low-pressure circuit is connected, so that the high-pressure oil in the first cavity is discharged through the low-pressure circuit.

[0008] In some embodiments, the first valve core includes: A drive piston is disposed within the first cavity and can slide along the axial direction under the action of oil in the first inlet chamber; A first valve seat is slidably disposed within the first cavity and at the end of the driving piston. The first valve seat has an interior cavity extending along the axial direction, and a through hole on its sidewall communicating with the interior cavity of the first valve seat and the first liquid outlet cavity. A first spring for providing restoring force to the drive piston is disposed between the drive piston and the partition of the valve body.

[0009] In some embodiments, the second valve core includes: The second valve seat is disposed between the limiting seat and the first valve core. There is a gap between the outer side of the second valve seat and the inner side wall of the valve body. The interior of the second valve seat has a cavity extending along the axial direction. A sliding member is slidably disposed within the cavity of the second valve seat and has a gap between it and the inner wall of the second valve seat. The second valve core achieves secondary regulation of the brake fluid circuit through the sequential separation of the sliding member and the second valve seat. A second spring for providing restoring force to the slider is disposed between the slider and the partition of the valve body.

[0010] In some embodiments, the high-pressure accumulator has sufficient liquid storage capacity and a maximum operating pressure of 20 MPa, enabling it to meet multiple braking requirements and providing higher braking pressure and braking deceleration for the hydraulic control device.

[0011] Secondly, a control unit is provided, characterized in that it includes the above-mentioned hydraulic control device, and further includes: The ECU controller is located in the valve body of the control unit and is used to adjust the pressure in the brake fluid circuit in real time. A brake, wherein the inlet of the brake is connected to the second outlet chamber of the hydraulically controlled directional valve; A normally closed solenoid valve, electrically connected to the ECU controller, includes a first normally closed solenoid valve and a second normally closed solenoid valve. The inlet of the first normally closed solenoid valve is connected to the internal oil circuit of the high-pressure accumulator. The brake oil circuit between the first normally closed solenoid valve and the second normally closed solenoid valve is connected to the internal oil circuit of the brake. When pressure needs to be built up, the ECU controller opens the first normally closed solenoid valve, allowing the high-pressure oil in the high-pressure accumulator to enter the brake. When pressure needs to be reduced, the ECU controller closes the first normally closed solenoid valve and opens the second normally closed solenoid valve, allowing the high-pressure oil to be discharged. A normally open solenoid valve, electrically connected to the ECU controller, includes a first normally open solenoid valve and a second normally open solenoid valve. The outlet of the first normally open solenoid valve communicates with the first inlet chamber, and the second normally open solenoid valve is disposed in the oil circuit formed by the brake and the second outlet chamber; and Multiple hydraulic sensors are evenly arranged within the control unit and electrically connected to the ECU controller to monitor hydraulic changes within the control unit.

[0012] Thirdly, a brake-by-wire system is provided, comprising two of the aforementioned hydraulic control units, and further comprising: The reservoir for supplying and recovering brake fluid is connected to the first outlet chamber and the outlets of all the second normally closed solenoid valves. The brake master cylinder integrated unit, used to provide brake pedal feedback and directional driving force for the hydraulic directional valve, includes a brake master cylinder, a brake pedal, and a pedal simulator. The internal oil circuit of the brake master cylinder is connected to the inner cavity of the oil reservoir. The brake master cylinder is connected to the corresponding first inlet chamber through two first normally open solenoid valves in the control unit. The brake pedal is located at the end of the brake master cylinder. A displacement sensor for monitoring the brake signal is located between the brake pedal and the brake master cylinder. The displacement sensor is electrically connected to the ECU controller. The pedal simulator is located in the valve body of the control unit and is connected to the first circuit outlet of the brake master cylinder. When the brake pedal is depressed, the ECU controller closes the two first normally open solenoid valves through the brake signal from the displacement sensor, allowing the oil in the brake master cylinder to enter the pedal simulator. The combined spring in the pedal simulator provides pedal force feedback, resulting in a more comfortable brake pedal feel. The plunger pump is connected to the high-voltage accumulator of both of the aforementioned control units; The two control units are a first control unit and a second control unit, respectively. The circuit formed by the first control unit and the master cylinder is a first braking circuit, and the circuit formed by the second control unit and the master cylinder is a second braking circuit. The ECU controller can adjust the oil pressure in the first braking circuit and the second braking circuit respectively.

[0013] In some embodiments, when the brake-by-wire system enters mechanical backup mode due to power failure, the high-pressure hydraulic fluid built up in the master cylinder of the brake pedal enters the first control unit and the second control unit respectively. The hydraulic directional valve corresponding to each control unit performs the following reversing action: the hydraulic fluid in the first inlet chamber pushes the corresponding first valve core to move along the axial direction until it contacts the corresponding second valve core. At this time, the low-pressure circuit, the primary oil circuit, and the secondary oil circuit are disconnected; subsequently, the first valve core continues to push the second valve core along the axial direction... The valve moves along the axial direction until it contacts the limiting seat. At this time, the low-pressure circuit and the secondary oil circuit are both disconnected, while the primary oil circuit is connected, allowing a small amount of oil from the high-pressure accumulator to enter the primary oil circuit. When the pressure in the second outlet chamber and the high-pressure accumulator tends to balance, the first valve core pushes the second valve core away from the inner wall of the valve body. At this time, the low-pressure circuit and the primary oil circuit are both disconnected, while the secondary oil circuit is open, allowing the oil in the high-pressure accumulator to enter the second outlet chamber through the secondary oil circuit. Then, the high-pressure oil in the second outlet chamber enters the corresponding brake through the second normally open solenoid valve, achieving wheel braking.

[0014] Fourthly, a brake-by-wire method is provided, applicable to the aforementioned brake-by-wire system, comprising the following steps: When the brake-by-wire system is in normal braking mode and the ECU controller detects that the pressure in the high-pressure accumulator is lower than the set value, the ECU controller drives the plunger pump to work. At this time, the two high-pressure accumulators are in the pressure-building state. When the brake-by-wire system is in normal braking mode and the ECU controller detects an increase in the displacement signal of the brake pedal, the ECU controller closes the first normally open solenoid valve and the second normally open solenoid valve of the two control circuits and opens the first normally closed solenoid valve, allowing the high-pressure oil in the accumulator to enter the brake to achieve braking. When the brake-by-wire system is in normal braking mode and the ECU controller detects a decrease in the displacement signal of the brake pedal, the ECU controller opens the second normally closed solenoid valve, allowing the high-pressure oil in the braking circuit to flow back to the oil reservoir to achieve initial pressure reduction; when the ECU controller detects zero displacement signal of the brake pedal, the ECU controller closes the first normally closed solenoid valve and the second normally closed solenoid valve, and opens the first normally open valve and the second normally open solenoid valve to achieve complete pressure relief of the entire system; When the brake-by-wire system is in mechanical backup braking mode due to power failure, the high-pressure oil built up in the master cylinder by the brake pedal enters the corresponding hydraulic directional valve through the two first normally open solenoid valves and drives the corresponding hydraulic directional valve to perform a directional action; then, the high-pressure oil in the hydraulic directional valve enters the corresponding brake through the corresponding second normally open solenoid valve to achieve wheel braking.

[0015] The beneficial effects of this invention are: the hydraulic control device integrates a high-pressure accumulator and a hydraulically controlled directional valve. The high-pressure accumulator serves as a power source and can meet the braking requirements of the braking system under normal energized conditions. The hydraulically controlled directional valve adopts a two-stage valve structure design, which can release the hydraulic pressure stored in the high-pressure accumulator and ensure that the entire braking system can stably output braking force even under power failure conditions. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the hydraulic control device provided in one embodiment of the present invention; Figure 2 This is a schematic diagram of the working principle of the control unit provided in one embodiment of the present invention; Figure 3 This is a schematic diagram of the working principle of the brake-by-wire system provided in one embodiment of the present invention; Detailed Implementation

[0018] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0019] This invention provides a hydraulic control device that solves the problem of insufficient braking performance in heavy-duty vehicles under motor power failure conditions, making it impossible to meet the mandatory requirements for emergency braking deceleration. This invention also provides a control unit using this hydraulic control device, and a brake-by-wire system using this control unit.

[0020] like Figure 1 As shown, in one embodiment, the hydraulic control device 30 includes a hydraulically controlled directional valve 301 and a high-pressure accumulator 302.

[0021] The hydraulic directional valve 301 is used to regulate the braking path and includes a valve body 303, a limit seat 304, and two valve cores. The valve body 303 has multiple interconnected cavities. The limit seat 304 and the two valve cores are sequentially arranged in the first cavity 3011 of the valve body 303. Both valve cores can slide back and forth along the axis of the first cavity 3011 and each has an oil passage extending along the axial direction but not completely connected inside. These are the first valve core 305 and the second valve core 306, respectively. The first valve core 305 serves as a switch connecting its internal oil passage to the corresponding oil cavity. The outer side of the second valve core 306 forms an axially extending external oil passage between the outer side and the inner wall of the valve body 303. The second valve core 306 and the limit seat 304 together serve as a switch connecting the internal and external oil passages of the second valve core 306 to the corresponding oil cavity. In one embodiment, such as Figure 1As shown, the hydraulic directional valve 301 includes a valve body 303, a first mounting base 3018, a second mounting base 3017, a limiting seat 304, a first valve core 305, and a second valve core 306. The valve body 303 has multiple communicating cavities, including a first cavity 3011, a first inlet cavity 3012, a first outlet cavity 3013, a second inlet cavity 3014, and a second outlet cavity 3015. The first cavity 3011, first inlet cavity 3012, first outlet cavity 3013, second inlet cavity 3014, and second outlet cavity 3015 are all connected to the first cavity 3011. The first mounting base 3018 is fixed within the first cavity 3011 by a sealing ring. The second mounting base 3017 is fixed within the cavity of the left section of the first mounting base 3018 by a sealing ring. The limiting seat 304 includes a base 3041, a limiting core 3042, and a third spring 3043. The base 3041 is slidably connected to the cover 3016 of the valve body 303 via a fourth spring 3044. The limiting core 3042 is disposed in the cavity of the base 3041 and connected to the base 3041 via a third spring 3043. The first valve core 305 includes a driving piston 3051, a first valve seat 3052, and a first spring 3053. The driving piston 3051 is disposed at the right end of the first cavity 3011 and can slide along the axial direction under the action of the oil in the first inlet cavity 3012. The first valve seat 3052 is slidably disposed in the cavity of the first mounting base 3018 and located at the left end of the driving piston 3051. The interior of the first valve seat 3052 has a cavity extending along the axial direction. The cavity has an internal cavity and a through hole for the first liquid outlet cavity 3013 on its side wall. The first liquid outlet cavity 3013 and the internal oil passage of the first valve core 305 together form a low-pressure circuit 3055. The left end of the first valve seat 3052 is connected to the partition of the valve body 303 through the fifth spring 3054. The first spring 3053 is disposed between the drive piston 3051 and the first mounting seat 3018 to provide a restoring force for the drive piston 3051. The second valve core 306 includes a second valve seat 3061, a sliding member 3062 and a second spring 3063. The second valve seat 3061 is slidably disposed in the second mounting seat 3017 and the gap between the two extending along the axial direction constitutes the second valve core. The external oil passage of valve core 306 is provided. Sliding member 3062 can reciprocate along the axis within the cavity of second valve seat 3061. The gap between sliding member 3062 and second valve seat 3061 forms the internal oil passage of second valve core 306. Second inlet chamber 3014 and second outlet chamber 3015, through the internal and external oil passages of second valve core 306, respectively form primary oil passage 3064 and secondary oil passage 3065. Secondary regulation of the brake fluid circuit is achieved by sequentially separating sliding member 3062 and second valve seat 3061 from limit seat 304. Secondary spring 3063, used to provide restoring force to sliding member 3062, is disposed between sliding member 3062 and the partition of valve body 303. In one embodiment, sliding member 3062 is a push rod.

[0022] The high-pressure accumulator 302 is powered by regulating the internal hydraulic pressure of the hydraulic directional valve 301. The internal oil circuit of the high-pressure accumulator 302 is connected to the first cavity 3011 through the second inlet chamber 3014 of the valve body 303. In one embodiment, the high-pressure accumulator 302 has sufficient liquid storage volume and a maximum working pressure of 20MPa, which can meet the needs of multiple braking operations and provide higher braking pressure and braking deceleration for the hydraulic control device 30. When multiple high-pressure accumulators 302 are configured, a check valve can be set between the high-pressure accumulators 302 for isolation to achieve failure protection.

[0023] In one embodiment, such as Figure 1 As shown, the oil in the first inlet chamber 3012 pushes the drive piston 3051 and the first valve seat 3052 to move to the left until they contact the sliding member 3062. At this time, the low-pressure circuit 3055, the primary oil circuit 3064, and the secondary oil circuit 3065 are all disconnected. Afterward, the first valve core 305 continues to push the sliding member 3062 to the left until it contacts the limiting core 3042. At this time, the low-pressure circuit 3055 and the secondary oil circuit 3065 are both disconnected, while the primary oil circuit 3064 is connected. This allows a small amount of oil in the high-pressure accumulator 302 to enter the primary oil circuit 3064. When the pressure in the second outlet chamber 3015 and the high-pressure accumulator 302 tends to be balanced, the first valve core 305 pushes the second valve seat 3061 to disengage from the second mounting base 3017. At this time, the low-pressure circuit 3055 and the primary oil circuit 3064 are both disconnected, and the secondary oil circuit 3065 is open, allowing the oil in the high-pressure accumulator 302 to enter the second outlet chamber 3015 through the secondary oil circuit 3065.

[0024] In one embodiment, such as Figure 1 As shown, when the oil in the first inlet chamber 3012 stops pushing the first valve core 305, both the first valve core 305 and the second valve core 306 move to the right under the restoring force of the spring. At this time, the primary oil circuit 3064, the secondary oil circuit 3065, and the low-pressure circuit 3055 are all in the disconnected state. When the oil pressure in the first inlet chamber 3012 drops, both the first valve core 305 and the second valve core 306 move to the right back to their original positions. At this time, the primary oil circuit 3064 and the secondary oil circuit 3065 are in the disconnected state, and the low-pressure circuit 3055 is in the connected state, so that the high-pressure oil in the first cavity 3011 is discharged through the low-pressure circuit 3055.

[0025] like Figure 2 As shown, in one embodiment, a control unit 20 is provided. This control unit 20 includes, in addition to the hydraulic control device 30 mentioned in the above embodiments, an ECU controller 201, a brake 202, a normally closed solenoid valve 203, a normally open solenoid valve 204, and multiple hydraulic sensors 205. In one embodiment, as... Figure 1As shown, the ECU controller 201 is highly integrated into the valve body of the control unit 20, and is electrically connected to the normally closed solenoid valve 203, the normally open solenoid valve 204, and multiple hydraulic sensors 205. It is used to identify sensor signals, control the opening and closing of the solenoid valves, and adjust the pressure in the brake fluid circuit in real time. The inlet of the brake 202 is connected to the second outlet chamber 3015 of the hydraulic directional valve 301. The normally closed solenoid valve 203 includes a first normally closed solenoid valve 2031 and a second normally closed solenoid valve 2032. The inlet of the first normally closed solenoid valve 2031 is connected to the internal oil circuit of the high-pressure accumulator 302, and the brake fluid circuit between the first normally closed solenoid valve 2031 and the second normally closed solenoid valve 2032 is connected to the internal oil circuit of the brake 202. When pressure needs to be built up... When pressure is applied, the ECU controller 201 opens the first normally closed solenoid valve 2031, allowing the high-pressure oil in the high-pressure accumulator 302 to enter the brake 202; when pressure reduction is required, the ECU controller 201 closes the first normally closed solenoid valve 2031 and opens the second normally closed solenoid valve 2032, allowing the high-pressure oil to be discharged; the normally open solenoid valve 204 includes a first normally open solenoid valve 2041 and a second normally open solenoid valve 2042, the outlet of the first normally open solenoid valve 2041 is connected to the first inlet chamber 3012, and the second normally open solenoid valve 2042 is arranged in the oil circuit formed by the brake 202 and the second outlet chamber 3015; multiple hydraulic sensors 205 are evenly arranged in the control unit 20 to monitor the hydraulic changes inside the control unit 20.

[0026] like Figure 2As shown, in one embodiment, a brake-by-wire system 10 is provided, which, in addition to including two hydraulic control units 20 mentioned in the above embodiments, also includes an oil reservoir 101, a brake master cylinder integrated unit 102, a piston pump 103, and an ABS / ESC system 104. The oil reservoir 101 is connected to the outlet of the first outlet chamber 3013 and all the outlets of the second normally closed solenoid valves 2032, and is used to recover brake fluid. When pressure reduction is required, the ECU controller 201 closes the first normally closed solenoid valve 2031 and opens the second normally closed solenoid valve 2032, allowing the high-pressure oil to flow back into the oil reservoir 101. The brake master cylinder integrated unit 102 is used to provide brake pedal feedback and provide directional driving force for the hydraulic control directional valve 301. It includes a brake master cylinder 1021, a brake pedal 1022, and a pedal simulator 1023. The internal oil circuit of the brake master cylinder 1021 is connected to the inner cavity of the oil reservoir 101 through a small oil reservoir 1024. The brake master cylinder 1021 is connected to the corresponding first inlet chamber 3012 through the first normally open solenoid valves 2041 in the two control units 20. The brake pedal 1022 is located at the end of the brake master cylinder 1021. The brake pedal 1022 and the brake master cylinder are connected. A displacement sensor 1021a for monitoring braking signals is located between 1021 and is electrically connected to the ECU controller 201. A pedal simulator 1023 is located in the valve body of the control unit 20 and is connected to the first circuit outlet of the master cylinder 1021 through a rigid pipe. A sensor 1023a is located at the left end of the pedal simulator 1023. When the brake pedal 1022 is pressed, the ECU controller 201 closes the two first normally open solenoid valves 2041 through the braking signal from the displacement sensor 1021a, so that the oil in the master cylinder 1021 enters the pedal simulator 1023. The combined spring in the pedal simulator 1023 provides feedback on the pedal force, resulting in a more comfortable braking feel. The plunger pump 103 is connected to the high-pressure accumulators 302 of both control units 20. The ABS / ESC system 104 is located in the hydraulic control directional valve 301 and the oil circuit of the brake 202. In one embodiment, the two control units 20 are a first control unit 20A and a second control unit 20B, respectively. The circuit formed by the first control unit 20A and the brake master cylinder 1021 is the first brake circuit, and the circuit formed by the second control unit 20B and the brake master cylinder 1021 is the second brake circuit. The ECU controller can adjust the hydraulic pressure in the first brake circuit and the second brake circuit respectively. In one embodiment, the brake pedal 1022 adopts a decoupled design. The hydraulic pressure established in the brake master cylinder 1021 when the driver presses the brake pedal 1022 is only connected to the pedal simulator 1023 for pedal force feedback, providing a good pedal feel.

[0027] In one embodiment, such as Figure 2As shown, when the brake-by-wire system 10 enters the mechanical backup mode due to power failure, the high-pressure oil established in the brake master cylinder 1021 by the brake pedal 1022 enters the first control unit 20A and the second control unit 20B respectively. The hydraulic control directional valve 301 corresponding to each control unit 20 performs the following reversing action: the oil in the first inlet chamber 3012 pushes the corresponding first valve core 305 to move along the axial direction until it contacts the corresponding second valve core 306. At this time, the low-pressure circuit 3055, the primary oil circuit 3064 and the secondary oil circuit 3065 are all in the disconnected state; then, the first valve core 305 continues to push the second valve core 306 to move along the axial direction until... When the pressure reaches the limit seat 304, the low-pressure circuit 3055 and the secondary oil circuit 3065 are both disconnected, while the primary oil circuit 3064 is connected, allowing a small amount of oil from the high-pressure accumulator 302 to enter the primary oil circuit 3064. When the pressure in the second outlet chamber 3015 and the high-pressure accumulator 302 tends to balance, the first valve core 305 pushes the second valve core 306 away from the inner wall of the valve body 303. At this time, the low-pressure circuit 3055 and the primary oil circuit 3064 are both disconnected, while the secondary oil circuit 3065 is open, allowing the oil in the high-pressure accumulator 302 to enter the second outlet chamber 3015 through the secondary oil circuit 3065. Then, the high-pressure oil in the second outlet chamber 3015 enters the corresponding brake 202 through the second normally open solenoid valve 2042, achieving wheel braking.

[0028] like Figure 2 As shown, in one embodiment, a brake-by-wire method is provided, applicable to the brake-by-wire system 10 mentioned in the above embodiments, comprising the following steps: When the brake-by-wire system 10 is in normal braking mode and the ECU controller 201 detects that the pressure in the high-pressure accumulator 302 is lower than the set value, the ECU controller 201 drives the plunger pump 103 to work. At this time, the two high-pressure accumulators 302 are in the pressure-building state. When the brake-by-wire system 10 is in normal braking mode and the ECU controller 201 detects an increase in the displacement signal of the brake pedal 1022, the ECU controller 201 closes the first normally open solenoid valve 2041 and the second normally open solenoid valve 2042 of the two control circuits and opens the first normally closed solenoid valve 2031, so that the high-pressure oil in the accumulator enters the brake 202 to achieve braking. In one embodiment, when the driver performs a braking operation, the ECU controller 201 performs a pressure-building action according to the increase in displacement of the brake pedal 1022: the ECU controller 201 closes the first normally open solenoid valve 2041 and the second normally open solenoid valve 2042, and opens the first normally closed solenoid valve 2031. At this time, the high pressure in the high-voltage accumulator 302 will enter the brake 202 through the first normally closed solenoid valve 2031, thereby realizing vehicle braking. When the brake-by-wire system 10 is in normal braking mode and the ECU controller 201 detects a decrease in the displacement signal of the brake pedal 1022, the ECU controller 201 opens the second normally closed solenoid valve 2032, allowing the high-pressure oil in the braking circuit to flow back to the oil reservoir 101 to achieve initial pressure reduction; when the ECU controller 201 detects zero displacement signal of the brake pedal 1022, the ECU controller 201 closes the first normally closed solenoid valve 2031 and the second normally closed solenoid valve 2032, and opens the first normally open solenoid valve 2041 and the second normally open solenoid valve 2042 to achieve complete pressure relief of the entire system; In one embodiment, when the driver releases the brake pedal 1022, the ECU controller 201 performs a pressure relief action based on the reduction in the displacement of the brake pedal 1022: the ECU controller 201 opens the second normally closed solenoid valve 2032, allowing the high-pressure oil in the brake circuit to flow back into the oil reservoir 101 to achieve initial pressure reduction. When the brake pedal 1022 returns to its initial position, the ECU controller 201 closes the first normally closed solenoid valve 2031 and the second normally closed solenoid valve 2032, and opens the first normally open solenoid valve 2041 and the second normally open solenoid valve 2042, achieving complete pressure relief of the entire system.

[0029] In one embodiment, the vehicle is equipped with external signal recognition devices such as vision sensors, millimeter-wave radar, and lidar. The ECU controller 201 can collect signal changes from these external signal recognition devices and actively issue commands to perform pressure build-up or pressure relief actions (the execution steps are the same as in conventional braking mode), thereby meeting the needs of Level 2 and above assisted driving. When the ECU controller 201 detects that the distance to an obstacle in front of the vehicle is close to the alarm value, the ECU controller 201 will issue a pressure build-up command, closing the second normally open solenoid valve 2042 and opening the first normally closed solenoid valve 2031. The high-pressure oil in the high-pressure accumulator 302 enters the brake 202 to achieve vehicle deceleration. When the ECU controller 201 detects that the obstacle alarm in front of the vehicle has been cleared, the ECU controller 201 will perform a pressure relief action, opening the second normally closed solenoid valve 2032, allowing the high-pressure oil in the brake line to flow back to the oil reservoir 101 to achieve pressure reduction.

[0030] When the brake-by-wire system 10 is in mechanical backup braking mode due to power failure, the high-pressure oil established in the master cylinder 1021 of the brake pedal 1022 enters the corresponding hydraulic directional valve 301 through two first normally open solenoid valves 2041 and drives the corresponding hydraulic directional valve 301 to perform a reversing action; then, the high-pressure oil in the hydraulic directional valve 301 enters the corresponding brake 202 through the corresponding second normally open solenoid valve 2042 to achieve wheel braking.

[0031] The hydraulic control device 30 provided by this invention integrates a high-pressure accumulator 302 and a hydraulically controlled directional valve 301. In the event of a power failure, the hydraulically controlled directional valve 301 can be manually driven to release the high-pressure oil stored in the high-pressure accumulator 302, compensating for the inability of heavy-duty vehicles to obtain the required braking force through the brake pedal. The hydraulically controlled directional valve 301 adopts a two-stage valve structure design, allowing for easy opening and a follow-up function. It can maintain stable pressure balance and perform pressure increase / decrease actions according to the depth of the brake pedal, achieving smooth vehicle control and providing a better pedal feel. Furthermore, the entire brake-by-wire system 10 is equipped with two independent control modules 20, connected to the front and rear axles of the vehicle respectively, meeting the H-type layout requirements of heavy-duty commercial vehicle braking systems. This enables the feasibility of equipping 8-12 ton heavy-duty vehicles with hydraulic braking systems, greatly improving the overall vehicle economy and comfort.

[0032] The above description is merely a preferred embodiment of one or more embodiments of this specification and is not intended to limit the scope of one or more embodiments of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this specification should be included within the protection scope of one or more embodiments of this specification.

Claims

1. A hydraulic control device, characterized in that, include: A hydraulic directional valve for regulating the braking path includes a valve body, a limit seat, and two valve cores, wherein the valve body has multiple communicating cavities. The limiting seat and the two valve cores are sequentially disposed in the first cavity of the valve body. Both valve cores can slide back and forth along the axis of the first cavity and each has an oil passage extending along the axial direction but not completely connected inside. The two valve cores are a first valve core and a second valve core. The first valve core serves as a switch connecting the internal oil passage of the first valve core with the corresponding oil chamber. An external oil passage extending along the axial direction is formed between the outer side of the second valve core and the inner wall of the valve body. The second valve core and the limiting seat together serve as a switch connecting the internal and external oil passages of the second valve core with the corresponding oil chamber. A high-pressure accumulator provides power by regulating the internal hydraulic pressure of the hydraulically controlled directional valve. The internal oil circuit of the high-pressure accumulator is connected to the first cavity through the second inlet chamber of the valve body. The first inlet chamber, the first outlet chamber, the second inlet chamber, and the second outlet chamber of the valve body are all connected to the first cavity; the second inlet chamber and the second outlet chamber form a primary oil circuit and a secondary oil circuit respectively through the internal oil circuit and the external oil circuit of the second valve core; the first outlet chamber and the internal oil circuit of the first valve core together form a low-pressure circuit; The oil in the first inlet chamber pushes the first valve core to move along the axial direction until it contacts the second valve core. At this time, the low-pressure circuit, the primary oil circuit, and the secondary oil circuit are disconnected. Then, the first valve core continues to push the second valve core to move along the axial direction until it contacts the limiting seat. At this time, the low-pressure circuit and the secondary oil circuit are both disconnected, and the primary oil circuit is connected, allowing a small amount of oil in the high-pressure accumulator to enter the primary oil circuit. When the pressure in the second outlet chamber tends to be balanced with that in the high-pressure accumulator, the first valve core pushes the second valve core to disengage from the inner wall of the valve body. At this time, the low-pressure circuit and the primary oil circuit are both disconnected, and the secondary oil circuit is open, allowing the oil in the high-pressure accumulator to enter the second outlet chamber through the secondary oil circuit. When the oil in the first inlet chamber stops pushing the first valve core, the first valve core and the second valve core move in opposite directions along the axis. At this time, the first-stage oil circuit, the second-stage oil circuit and the low-pressure circuit are all in the disconnected state. When the oil pressure in the first inlet chamber drops, the first valve core and the second valve core move back to their original positions in opposite directions along the axis. At this time, the primary oil circuit and the secondary oil circuit are both disconnected, and the low-pressure circuit is connected, so that the high-pressure oil in the first cavity is discharged through the low-pressure circuit.

2. The hydraulic control device according to claim 1, characterized in that, The first valve core includes: A drive piston is disposed within the first cavity and can slide along the axial direction under the action of oil in the first inlet chamber; A first valve seat is slidably disposed within the first cavity and at the end of the driving piston. The first valve seat has an interior cavity extending along the axial direction, and a through hole on its sidewall communicating with the interior cavity of the first valve seat and the first liquid outlet cavity. A first spring for providing restoring force to the drive piston is disposed between the drive piston and the partition of the valve body.

3. The hydraulic control device according to claim 1, characterized in that, The second valve core includes: The second valve seat is disposed between the limiting seat and the first valve core. There is a gap between the outer side of the second valve seat and the inner side wall of the valve body. The interior of the second valve seat has a cavity extending along the axial direction. A sliding member is slidably disposed within the cavity of the second valve seat and has a gap between it and the inner wall of the second valve seat. Secondary regulation of the brake fluid circuit is achieved by sequentially separating the sliding member and the second valve seat from the limiting seat. A second spring for providing restoring force to the slider is disposed between the slider and the partition of the valve body.

4. The hydraulic control device according to claim 1, characterized in that: The high-pressure accumulator has sufficient liquid storage capacity and a maximum working pressure of 20MPa, which can meet the needs of multiple braking operations and provide higher braking pressure and braking deceleration for the hydraulic control device.

5. A control unit, characterized in that, The hydraulic control device comprising any one of claims 1-4 further comprises: The ECU controller is located in the valve body of the control unit and is used to adjust the pressure in the brake fluid circuit in real time. A brake, wherein the inlet of the brake is connected to the second outlet chamber of the hydraulically controlled directional valve; A normally closed solenoid valve, electrically connected to the ECU controller, includes a first normally closed solenoid valve and a second normally closed solenoid valve. The inlet of the first normally closed solenoid valve is connected to the internal oil circuit of the high-pressure accumulator. The brake oil circuit between the first normally closed solenoid valve and the second normally closed solenoid valve is connected to the internal oil circuit of the brake. When pressure needs to be built up, the ECU controller opens the first normally closed solenoid valve, allowing the high-pressure oil in the high-pressure accumulator to enter the brake. When pressure needs to be reduced, the ECU controller closes the first normally closed solenoid valve and opens the second normally closed solenoid valve, allowing the high-pressure oil to be discharged. A normally open solenoid valve, electrically connected to the ECU controller, includes a first normally open solenoid valve and a second normally open solenoid valve. The outlet of the first normally open solenoid valve communicates with the first inlet chamber, and the second normally open solenoid valve is disposed in the oil circuit formed by the brake and the second outlet chamber; and Multiple hydraulic sensors are evenly arranged within the control unit and electrically connected to the ECU controller to monitor hydraulic changes within the control unit.

6. A brake-by-wire system, characterized in that, Including the two hydraulic control units described in claim 5 above, and further comprising: The reservoir for supplying and recovering brake fluid is connected to the first outlet chamber and the outlets of all the second normally closed solenoid valves. The brake master cylinder integrated unit, used to provide brake pedal feedback and directional driving force for the hydraulic directional valve, includes a brake master cylinder, a brake pedal, and a pedal simulator. The internal oil circuit of the brake master cylinder is connected to the inner cavity of the oil reservoir. The brake master cylinder is connected to the corresponding first inlet chamber through two first normally open solenoid valves in the control unit. The brake pedal is located at the end of the brake master cylinder. A displacement sensor for monitoring the brake signal is located between the brake pedal and the brake master cylinder. The displacement sensor is electrically connected to the ECU controller. The pedal simulator is located in the valve body of the control unit and is connected to the first circuit outlet of the brake master cylinder. When the brake pedal is depressed, the ECU controller closes the two first normally open solenoid valves through the brake signal from the displacement sensor, allowing the oil in the brake master cylinder to enter the pedal simulator. The combined spring in the pedal simulator provides pedal force feedback, resulting in a more comfortable brake pedal feel. The plunger pump is connected to the high-voltage accumulator of both of the aforementioned control units; The two control units are a first control unit and a second control unit, respectively. The circuit formed by the first control unit and the master cylinder is a first braking circuit, and the circuit formed by the second control unit and the master cylinder is a second braking circuit. The ECU controller can adjust the oil pressure in the first braking circuit and the second braking circuit respectively.

7. The brake-by-wire system according to claim 6, characterized in that: When the brake-by-wire system enters mechanical backup mode due to power failure, the high-pressure hydraulic fluid built up in the master cylinder of the brake pedal enters the first control unit and the second control unit respectively. The hydraulic directional valve corresponding to each control unit performs the following reversing action: the hydraulic fluid in the first inlet chamber pushes the corresponding first valve core to move along the axial direction until it contacts the corresponding second valve core. At this time, the low-pressure circuit, the primary oil circuit, and the secondary oil circuit are disconnected. Then, the first valve core continues to push the second valve core to move along the axial direction until it contacts the limit seat. At this time, the low-pressure circuit and the... Both secondary oil circuits are disconnected, while the primary oil circuit is connected, allowing a small amount of oil from the high-pressure accumulator to enter the primary oil circuit. When the pressure in the second outlet chamber and the high-pressure accumulator tends to balance, the first valve core pushes the second valve core away from the inner wall of the valve body. At this time, both the low-pressure circuit and the primary oil circuit are disconnected, and the secondary oil circuit is open, allowing the oil in the high-pressure accumulator to enter the second outlet chamber through the secondary oil circuit. Subsequently, the high-pressure oil in the second outlet chamber enters the corresponding brake through the second normally open solenoid valve, achieving wheel braking.

8. A method for brake-by-wire, characterized in that, The brake-by-wire system according to claim 7 includes the following steps: When the brake-by-wire system is in normal braking mode and the ECU controller detects that the pressure in the high-pressure accumulator is lower than the set value, the ECU controller drives the plunger pump to work. At this time, the two high-pressure accumulators are in the pressure-building state. When the brake-by-wire system is in normal braking mode and the ECU controller detects an increase in the displacement signal of the brake pedal, the ECU controller closes the first normally open solenoid valve and the second normally open solenoid valve of the two braking circuits and opens the first normally closed solenoid valve, allowing the high-pressure oil in the accumulator to enter the brake to achieve braking. When the brake-by-wire system is in normal braking mode and the ECU controller detects a decrease in the displacement signal of the brake pedal, the ECU controller opens the second normally closed solenoid valve, allowing the high-pressure oil in the braking circuit to flow back to the oil reservoir to achieve initial pressure reduction; when the ECU controller detects zero displacement signal of the brake pedal, the ECU controller closes the first normally closed solenoid valve and the second normally closed solenoid valve, and opens the first normally open solenoid valve and the second normally open solenoid valve to achieve complete pressure relief of the entire system; When the brake-by-wire system is in mechanical backup braking mode due to power failure, the high-pressure oil built up in the master cylinder by the brake pedal enters the corresponding hydraulic directional valve through the two first normally open solenoid valves and drives the corresponding hydraulic directional valve to perform a directional action; then, the high-pressure oil in the hydraulic directional valve enters the corresponding brake through the corresponding second normally open solenoid valve to achieve wheel braking.

Images